A Simultaneous Solution to the ^6Li and ^7Li Big Bang Nucleosynthesis Problems from a Long-Lived Negatively-Charged Leptonic Particle

TL;DR

This paper proposes that a long-lived negatively-charged leptonic particle during Big Bang nucleosynthesis can simultaneously resolve the discrepancies in observed and predicted lithium isotopes, offering a novel solution to longstanding cosmological lithium problems.

Contribution

It introduces a new particle physics mechanism that explains lithium abundance anomalies by altering nuclear reaction pathways during the early universe.

Findings

Both ^6Li and ^7Li abundances can be matched to observations with this model.

The particle catalyzes additional nucleosynthesis reactions, reducing the need for stellar destruction explanations.

The solution is compatible with existing cosmological constraints.

Abstract

The $^6$Li abundance observed in metal poor halo stars exhibits a plateau similar to that for $^7$Li suggesting a primordial origin. However, the observed abundance of $^6$Li is a factor of $10^3$ larger and that of $^7$Li is a factor of 3 lower than the abundances predicted in the standard big bang when the baryon-to-photon ratio is fixed by WMAP. Here we show that both of these abundance anomalies can be explained by the existence of a long-lived massive, negatively-charged leptonic particle during nucleosynthesis. Such particles would capture onto the synthesized nuclei thereby reducing the reaction Coulomb barriers and opening new transfer reaction possibilities, and catalyzing a second round of big bang nucleosynthesis. This novel solution to both of the Li problems can be achieved with or without the additional effects of stellar destruction.